Katrina Cholera?

Watching broadcast images of the devastation caused by the rushing floodwaters of Hurricane Katrina was heartbreaking. But after the fury of the storm had passed, my concern continues to rise. When sanitary water systems and sewage systems are overwhelmed, contaminated water and food can lead to explosive epidemics of cholera.

During the 1994 Rwandan refugee crisis, cholera killed more than 20,000 people in just four short weeks.

When normal social structures breakdown in crisis, such as the dissolution of the Soviet Union at the end of the 20th century, epidemics of cholera can follow.

Along the Gulf Coast, without electrical power, without normal services, and with dead bodies floating in the water, the situation might seem ripe for an epidemic like cholera. What is it?

Cholera is caused by saltwater bacteria, Vibrio cholerae, that can thrive in people and in seawater. In an epidemic, people usually catch it from water, food, or other materials that have been contaminated by the stool of a cholera victim. And there can be a lot of stool! Cholera causes dramatic diarrhea, where it is possible to pass a volume of watery stool equal to one’s own body weight over the course of the illness. Obviously, this can be lethal –especially in children – without careful replacement of fluids and electrolytes (in fact, the first use of IV fluids was for treating cholera). The disease is stunningly rapid. The journey from first symptom to death can all take place in 12 to 48 hours. During epidemics, some people wake up happy, and are dead before bed. Is this likely after Hurricane Katrina?

Every year, cholera is a major killer of children in poor countries around the world, but because cholera (and typhoid) bacteria are not common along the gulf coast of the United States, it is unlikely that Katrina will lead to one of these epidemics. A rise in common respiratory infections and diarrhea illnesses is to be expected. And E. coli and Norwalk virus (the virus that causes epidemics on cruise ships) are both likely. Cholera is not. But not impossible.

Five people who survived the torrents of Hurricane Katrina have already died after becoming infected with Vibrio vulnificus, diarrhea-causing bacteria in the same family as cholera. Wading through contaminated water allowed the bacteria to enter open cuts on the skin. Vibrio vulnificus live in warm seawater. The disease is a less dangerous cousin of cholera because serious cases are usually concentrated among those with already poor health or compromised immune systems. But, according to the Centers for Disease Control and Prevention, if these bacteria infect the bloodstream, the infection is fatal about 50 percent of the time.

Dr. Julie Gerberding, the director of the Centers for Disease Control and Prevention, nevertheless said during a conference call/press conference on September 6 that toxic chemicals in the water are a greater concern than infection. Chemical and petroleum facilities have sustained major damage, and the extent of water pollution remains unknown.

The bottom line is that floodwater should be treated by people as if it were contaminated stool or blood. Avoiding contact with the water is best when possible, especially on parts of the body with open wounds.

Washing with clean soap and water is one of the most important ways to avoid infection. Unfortunately, clean water can be difficult to find. Alcohol-based hand sanitizers can be critical for keeping clean, and interrupting the chain of infection.

Dr. Greene is the founder of DrGreene.com (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.